FIG. 2.

Construction of ΔL4TbpA. The 5′ (striped) and 3′ (gray) PCR-amplified halves of tbpA were individually cloned into pCR2.1, which contains a gene encoding ampicillin resistance (stippled bar). This procedure resulted in plasmids pVCU206 and pVCU207, respectively. These inserts were excised and ligated together in pET21 producing pVCU208, which contained ΔL4tbpA, downstream of a T7 promoter (black bar). The position of the TbpA start codon is shown as an open arrow, and that of the TbpA stop codon is marked with an asterisk. Approximate positions of oligonucleotides are indicated by closed arrows, with their respective names indicated in parentheses.